Environmental Science and Pollution Research - Soil contamination by heavy metals is one of the major abiotic stresses that cause retarded plant growth and low productivity. Among the heavy metals,... 相似文献
The rising global population is inducing a fast increase in the amount of municipal waste and, in turn, issues of rising cost and environmental pollution. Therefore, alternative treatments such as waste-to-energy should be developed in the context of the circular economy. Here, we review the conversion of municipal solid waste into energy using thermochemical methods such as gasification, combustion, pyrolysis and torrefaction. Energy yield depends on operating conditions and feedstock composition. For instance, torrefaction of municipal waste at 200 °C generates a heating value of 33.01 MJ/kg, while the co-pyrolysis of cereals and peanut waste yields a heating value of 31.44 MJ/kg at 540 °C. Gasification at 800 °C shows higher carbon conversion for plastics, of 94.48%, than for waste wood and grass pellets, of 70–75%. Integrating two or more thermochemical treatments is actually gaining high momentum due to higher energy yield. We also review reforming catalysts to enhance dihydrogen production, such as nickel on support materials such as CaTiO3, SrTiO3, BaTiO3, Al2O3, TiO3, MgO, ZrO2. Techno-economic analysis, sensitivity analysis and life cycle assessment are discussed.
A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.
Environmental Science and Pollution Research - Upon screening for novel and potential biocompounds with larvicidal activities, we successfully isolated hamisonine (HMSN) a limonoid compound from... 相似文献
Silver nanoparticle (SNP) is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a
major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles.
A reduction in the amount of exopolysaccharides was observed after SNPs – B. pumilus culture supernatant interaction. The Fourier
transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the
interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray
di raction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity
compared to uncoated SNPs. Our studies suggested that the capping of nanoparticles by bacterially produced exopolysaccharides serve
as the probable mechanism of tolerance. 相似文献
Studies on ultrasound-assisted processes are gaining importance due to its effectiveness and facilitating green method in processing. Degreasing of skin/hide prior to tanning process is an important unit operation. Presence of large amounts of natural fat at the interior of skin/hide matrix makes degreasing process a challenging one. Conventionally, organic solvent and/or detergent based degreasing process are employed leading to environmental problems. In the present paper, the use of power ultrasound in aqueous degreasing process has been studied and compared with different degreasing systems. Glutaraldehyde pre-tanning has also been employed for carrying out the degreasing process at ultrasonic bath temperature. The results indicate that there is a significant increase in the degreasing efficiency due to the application of ultrasound. About 2-fold increase in fat removal has been observed due to the use of ultrasound as compared to control under the given process conditions. Comparing the degreasing efficiencies of the solvent with aqueous based ultrasonic processes, about 80% of the solvent degreasing efficiency could be obtained for aqueous degreasing process. This novel ultrasonic process helps in making aqueous degreasing process a viable option, which is eco-friendly even dispensing with temperature control measures. 相似文献
